Acoustic device



Mar. 3, 1925.

' 1,528,080 L. s. SCHER ACOUSTIC DEVI CE Filed Nov. 2, 1923 avwemto'c 76A 5. 501

@3311 A 64276744013 .SJ. I

max, @199 NBS/m Patented Mar. 3,. 1925.

UNIT D STATES PATeuT -o Flca LOUIS s. SOHEB, or imw YORK, n. Y.

acousrrc mwroll Application filer November ToaZZ whom it may concern):

Be it known that LOUIS S. SCHER,;& citizen of the United States, and resident of borough of Bronx, New York city, county of Bronx, State oflNew York, have invented certain new and useful Improvements in Acoustic Devices, of which the following is.

a specification. I

The invention relates to improvements in acoustic devices whereby sound waves may effectively be collected, intensified andtransmitted to a desired point, and more particularly to ear trumpets for aiding partially deaf persons to hear more distinctly, or for enabling persons of normal hearing to hear same effectively tothe ear with faithful reproduction of the'qua'lity of the sound received, and which will be comparatively inexpensive and simple in construction. Another object is the provision of such devices in which no use is made or required of vibrating diaphragms, electricity or electromagnetic means. Another object consists in the provision of an improved'system or chain of chambers or passages designedto effectively collect, and intensify and transmit sound waves, truly and without loss of quality to a desired point, regardless of whether or not such waves are transmitted directly into the ear of the user. the invention. consist in the provision of improved combinations of elements and details of construction, all as will be more fully described hereinafter in the following specification, and be particularlv pointed out in the appended claims.

Devices intended to aid hearing comprise those which operate mechanically, such as the well-known ear tiumpet and the like, and'those in which the received'sou nd waves cause a micro-phone to vary the flow of an electric current through a conductor which operates a telephone-receiver attached to the ear. In such electrical devices a battery Other objects of.

a, 1923., Serialno. 672,241.

must be carried in a pocketof the user, and this battery must be renewed frm t to time after various periods of service. By 7 my invention devices are provided which may be used on or removed from the ears in much the same simple manner as spectacles are positioned for use or removed in the case of a person whose vision needs aid, without the use of a battery or connections extending from" the body or pocketv of the user'to thehead. Existing mechanical devices, that is devices in aid of hearing which mitting intensified sounds without loss of quality because,. for. example, .of' the resonance of the parts, or the production of un" desired sounds due to the'rates of vibration natural to the parts.

In the preferredconstruction-I provide members which may readily be clipped to do not employ electricity, are generallyv cumbersome, and difficulty hasbeen' exper1-. enced in this classof instruments in trans the ears of the user and which will fit snug- -ly against the ear with short tubes extendmg into connection with the auditory canals of the ears. These members each comprise a series or chain of chambers or passages so arranged as effectively to collect, intensify and transmit sound vibrations to the auditory canal of the ear. passages referred to areso designed and arranged that the natural rates of vibration of their enclosed air columns will be of extremely 'high pitch. These air columns will not beset into vibration by the sound waves ordinarily received by the system,'sufiicient ly to sound their own individualnotes, because of the insufficient energy of the received waves. In case, however, sound vibrations of high frequency, corresponding to the natural rate of vibration of one of the chambers of the system, are received,

the air in this chamber may, because of the The chambers or various chambers of the system will each have a different naturalhi gh pitch rate of vibration, so that various notes of high pitch, and their harmonics, may thus be reinforced,-

if received. This seems to improve the quallty' of the sound received in such cases, and

to roundout various tones of musical selectrons rece1ved,\wh1le' not interfering with the fidelity of reproduction of the ordinary conversational tones. This is in contradistinction to various prior known devices having low-pitched resonance.

Generally speaking, the device employsa series of connected chambersor passages of gradually diminshingcross-sectional di" mensions which are similar to open ended pipes of short length, these chambers or arranged one within the other so as to bring the whole system into a small compass.

In order that the invention maybe more clearly understood attention is hereby directed to the accompanying drawings forming part of this app one embodiment. of the invention. In the to an ear ofthe user, this section being taken on line 11 of F ig. 2;

Fig. 2 is a vertical section taken on 22 of Fig 1; Y

Fig. 3 is an outside view of the device, and z Fig. 4 is an inner side view. It will be understood that the devices may each ear, or a single one may, of course, be .used, when the user is deaf in one ear-only. In .the drawings a single device only is shown. The direction of sound may better be ascertained. when both ear of the user.

are used. v

Referring to the drawings, the device comprises an outer or sound receiving chamber 1, preferably having a flat side 2 adapted to fit snugly against the outer surface'of the Chamber 1 is provided with a mouth 3 which preferably is comparativelyi wide. vOpposite to the flat inner side '2 of the chamber, there is an inclined and smoothly curved surface 4. which extends rearwardly from mouth 3 and curves around at the rear, as is indicated at 5, to

.join the rear end of the flat side 2. The outto join the side side 4 is curved transversely edges of the flat side 2.

The inner side 20f the chamber is pre' erably provided with side edges 6, 6, which 'so as to be inconspicuous in appearance.

It will be noted that chamber 1 is com passages conveniently and preferably-being paratively short, that is, its dimension rearwards from the mouth 3 is comparatively 'short, and also that the mouth 3 is comparatively wide, relatively to the length of v chamber 1, considering the width of the' mouth as the distance between, the ends of :side. edges 6, as shown in F ig.v 3, and the height of the mouth as the distance between the front edges of bottom 2 and top 4, Fig. 1. Within chamber 1 there. is provided an enclosing structure 8 which is mounted upon of the outer chamber, as is indicated at 1O.

The outerandinner portions 9-and, 10 are 7 connected by top and bottom side portions 11,11. Communication is hadbetween enclosure or chamber 8 and the outer chamber 1 by means of a comparatively long narrow slit" or opening 12 at the rear of chamber 8, and a short distance forward' from the rear curved surface 5 of chamber 1'.

- In the form of construction shown in the drawings a third chamber or link in the .be supplied in pairs, one to be worn on acoustic'series is provided by a member 13, which extends rearwardly within chamber .8 from a mouth 14. a short distance to the rear of the closed front surface 9 of chamber 8. This chamber 13 comprises a top portion 13 and side portions 13 (Fig. 2), and extends rearwardly a convenient distance, which, as shown in the drawings, may be about half the length of chamber 8, after which it curves inwardly aslshown' at 15 and merges with the short tube 16 which extends out through suitable openings in portion 2 of the outer chamber and portion 10 of chamber 8. The side walls 13 of chamber 13 preferably are inclined, as shown'in Fig. 2. for a distance back from mouth 14, so as to make mouth 14 as long as possible, the

inclination of these side walls 13 gradually diminishing as they go back from the mouth until they are at right angles to side 13 opposite the opening into tube 16. Tube 16 is preferably inclined somewhat forwardly, as shown in Fig. l, to fit more or less closely against the surface of the recess of the ear, known as the concha, 1T. When so positioned the end of tube 16 preferably abuts against the flesh surrounding the outer 7 end of the auditory canal 18 of the car.

.There is provided. in the form of construction shown in the drawings, a lip 20. which forms a continuation of the tube 16, and extends into the interior of chamber 13. This lip serves asa reflecting surfaceto assist in directing the sound waves which are set up in chamber 13 int-0 tube 16. Lip 20 may be" a portion of bottom plate 10 of chamber 8 and may conveniently be stamped up from bottom plate 10.

Preferably tube 16 is divided into a number of parallel passages by small division plates 19 extending forwardly or outwardly somewhat from the inner end of the tube. Means for detachably securing .the, device in position upon the ear are provided which may consist of a pair of curved springy wire members 21,21, which are secured at the rear to the inner side 2 of the chamber 1, as is indicated at 22, these wire clips then curving forwardly and outwardly. When the device is to be used the short tube 16 is inserted in position, as shown in Fig. 1, and the clips 21 pressed into position to extend behind the upper and lower fleshy portions of the ear, knownas the helix and the lobe, and then to curve around the same and clip over them. With this construction the device is detachably anchored both front 7 and rear, forward motion of the device being prevented by the engagement'of tube 16 with the forward surface of the concha of the ear, while rearward movement is pre-' vented by'clips 21 passing around the upper and lower front corners of the ear When the device isin use sound waves enter mouth 3 of the outer chamber and move rearwardly through the chamber, the density of the waves being increased and the intensity of the sound accordingly increased, because of the convergence of the sides of the ch'amber. At the rear of the chamber the Waves are reflected smoothly by the curved surface '5 behind the narrow slit 12, which forms. the opening for chamber or passage 8. The considerable disturbance to the rear of slot 12 is transmitted therethrough and sets'theair within chamber 8 into similar vibration. I

It will be seen that chamber 1 is in efl'ect an open ended pipe or air column, the natural rate of vibration of which is an octave higher than that of a closed pipe of the same length. Sincethe frequencies of .the soundwavesof air columns vary practically inversely as the length, and since chamber l constitutes a short column which may be, forexample, only about two inches long, it will be seen that the. natural rate of vibration of chamber 1 is high. It will be noted that the side edges 6 of chamber 1 taper inwardly with a comparatively slight inclination, the outer wall 1 preferably tapering or curving towards the flat side '2 somewhat more steeply, the shaping of these walls being adapted to reflect and compress the sound waves with the greatest efficiency The use ofthe comparatively small taper of edges 6 and the short length of chamber 1 results in the production at the rear of chamber 1 of a disturbance which may be considered' as a band of considerable length in .tively direct the sound ing provided by slot 12 is suiiicient to enable chamber 1 to act to a considerable extent as an open-ended pipe, as stated. Furthermore, the transmission of the succeeding condensations and rarefactions' through such a comparatively long narrow slot I believe to be much more effective than would be the case if the sound waves were intensified by a conical trumpet 'and caused to pass therefrom through a comparatively small round opening at the apex thereof, as in the usual device of the character of the ear trumpet, such constructions necessitating greater length of air column, and resulting in low pitched resonance.

- -The outer wall 4 of chamber 1 is preferably domed, as indicated in the drawings,

with an outward curve of greater radius adjacent the side edges 6, as is indicated at 23.

Upon passing through slot 12 the sound waves are permitted to expand somewhatnaturally until the walls of the chamber or passage 13 are encountered, the waves passing through the passage bounded by the outer wall 13 thereof and the wall 9 of chamber 8, and the side walls 13 and 11 of chambers "13. and 8, respectively. The advancing area of disturbance is compressed somewhat further laterally in its forward passage through chamber 8 because of the fact that the side walls 11 of chamber 8 converge inwardly somewhat as they approach the frontof the device (see Fig. 3). The waves are then reflected by the curved front walls 9 of chamber 8 and pass into the mouth 14 of chamber 13, which mouth, as shown is also a comparatively long narrow slot of suitable shape to receive the waves and to enable chamber 8 to act'as an openended column. The waves are intensified somewhat further within chamber 13 sincev the cross-sectional dimension thereof de creases toward the tube 16. The sound waves so intensified will be transmitted around the lip20 and through the short tube 16 directly into the auditory canal 18 of the ear, tube 16 and lip 20 forming the fourth aircolumn or chamber. The division plates 19 of this short tube 16 serve to more effecwa-ves forwardly through the tube.

It will thus be seen that the device comprises a series of connected chambers or passages of gradually diminishing cross-sectional dimensions through which sound waves will be transmitted smoothly and I naturally, but with an increasing comprestion portions of the advancing waves to get out-of phase with each other as they progress through the various chambers. Further a sufiicient area of opening is provided at the mouth of each chamber to enable each condensation or rarefaction approaching such opening to freely set the air within the succeeding chamber into similar vibration without interference or retardation of the advancing wave section at the opening. It

will likewise be noted that the volume of air in each chamber or link of the acoustic system is quite small so' that there will be slight inertia of the elastic medium to. impede transmission of.rapidly changing vibrations. It will also be seen that the columns of air in the various chambers or links are of different lengths, and that each of the same has a different natural frequency of high pitch, the frequency of vibration of the outer chamber 1 beingthe lowest of the system, so that various notes of high frequency, and their harmonics, willbe reinforced somewhat, when recelved, by resonance, but that the comparatively low pitched sounds most commonly received will not thus be reinforced or interfered with.

having low-pitched resoiiance, in which'a,

low roaris always'found to'accompany the speaking voice. It will likewise be noted that while the device in the form here shown delivers the intensified'sound vibrations directly, into the ear, the system described andillustratedmay be used for. delivering the intensified sound at another desired point. It should also be noted that the devices described may, if desired, be used in a multiple arrangement. That is, a plurality of such devices, three for example, may be arranged in a group, if desired, with their axesatangles to each other, but their sound receiving mouths faced; in the same direction, and the exit connections of the devices,

such as the tubes 16 described above, adja- I cent to each other. The various exit tubes in this case may all'be suitably curved to lead the sound waves passing'theret-hrough into a common exit tube, leading to the ear or to another desired point. In. such a case the intensity ofthe received sound will be increased, While maintaining the advantages of lack of low resonance qualities, etc., in-. herent in each individual device.

It should be understood that the invention is not limited strictly to the details of con struction whichjhave been particularly de-v scribed, but that the invention is considered to be of considerable breadth, as is evidenced by the following claims.-

What I claim is:

1. An aural device, comprising a sound collecting and intensifying chamber provided at the rear with a narrow. elongated space towards which the walls of the chamber continuously converge, a second, substantially flat, chamber, connecting with said space through an elongated narrow opening, running parallel to said'elongated space, the entrance end'of said second chamber being of a less cross sectional area than the portion of said. first chamber having the least cross sectional area, and means for transmitting sound waves from the interior of i said second chamber to adesired point. I

2. An acoustic device, comprising a series of more than two'connected chambers open-' ing one into the next and decreasingin cross sectional dimensions from oneto another, the entrance end of each chamber being of a cross sectional area no greater than the portion of the preceding chamber of smallest crosssectional area, the first chamber having a sound receiving mouth and the last having an exit connection, said chambers constituting short open-ended pipes the pitch of each of which is high, relative to the pitch of the usual human speaking voice.

3. An aural device, comprising a sound receiving chamber having a comparatively wide mouth, a short length rearwardly from said mouth, and opposite walls converging from said mouth to provide a narrow elongated space at thevrear and a second chamber extending away from said space and communicating therewith through a substantially straight narrow elongated slot,

parallel to said elongated space',-said first chamber having a curved surface for re- =flecting sound waves towards said slot.

4. An aural device,-comprisinga member one side of whichis substantially flat and adapted to bear directly against "the outer l surface of the ear to the user with a short tube extending therethrough at a forwardly inclined angle to rest against the surface T of the concha with its end aligned withthe v mouth of the auditory canal, said member having arms adapted to clip over the helix prisiiig 1 length from the first and lobe of the ear, said member being con- I structed to collect sound waves and to in tensi and transmit them to said tube.

5. ear trumpet, comprising a series of connected chambers decreasing gradually in cross sectional area, terminating in a tube leading directly into the audito canal of the ear and divided into a plurality of longitudinal passages.

6. An. acoustic device, comprising a series of more than two connected chambers, comshort open ended pipes opening one into e next and decreasing in cross sectional ,area from one to another, the first chamber having a sound receiving mouth and the last having an exit connection, said chambers containin air columns each having its own indivi ual natural rate of vibration, the lengths of all ofsaid columns being different, said columns decreasing in to the last, and bein so short thatthe natural rates of vibration thereof are greater than the usual rates of vibration of the human voice in speaking.

7. An acoustic device, comprising a series of more thantwo connected chambers opening one into the next and decreasing in cross sectional dimensions from one to another, the second carrying the sound waves back through the first in reverse direction and the third, within the second, again reversing the direction of the transmitted waves and carryin them outthrough a wall of the device, said second and third chambers being substantially flat and having straight elongated narrow mouths.

n ear trumpet comprising a chamber member having a broad face member adapted to fit snugly adjacent the human ear, said chamber member having an opening for the reception of sound waves, and a plurality of separate chambers therein adapted to increase the intensity of the sound transmitted therethrough, each of said chambers being of gradually diminishingcross section with the smaller end of one operatively connected with the larger end of the next, said larger end being of a cross sectional area no greater than that g of said smaller end of the preceding chamber, and said chamber member having an opening in said broad face through which the intensified. sounds are transmitted to the auditory canal of the car.

In testimony whereof I, have signed my name to this specification.

LOUIS S. 'SCHER. 

